1on1match.js

const chantoSort = (array) => {
  for (let i = array.length - 1; i > 0; i--) {
    let r = Math.floor(Math.random() * (i + 1));
    let tmp = array[i];
    array[i] = array[r];
    array[r] = tmp;
  }
  return array;
};

const splitArray = (array, n) =>
  array.reduce(
    (a, c, i) =>
      i % n == 0 ? [...a, [c]] : [...a.slice(0, -1), [...a[a.length - 1], c]],
    []
  );

const participants = [...Array(10).keys()];

let count = 0;
const sets = [];

for (let i = 0; i < 5; i++) {
  const shuffled = chantoSort([...participants]);
  sets.push(shuffled);
  count++;
}

console.log(sets.map((set, i) => `set ${i}: ${splitArray(set, 2).map((item, idx)=>(`room${idx}: ${item.join("-")}`))}`));